(1) Field of the Invention
This invention relates to an improvement in or relating to a latch device for locking and releasing a runner member carrying a webbing fastened at one part of the latter to the former and movable on a guide member, namely, a movable anchor in a so-called passive seat belt system.
(2) Description of the Prior Art
The movable anchor moves rearward on the guide rail and is locked to a latch of a latch device in association with each closure of its associated door. In association with each opening of the door, the movable anchor is in turn released from the latch of the latch device and moves forward on the guide rail. Accordingly, the webbing is allowed to take either occupant-restraining or occupant-releasing position.
In many of conventi,onal latch devices, latches which engage their corresponding movable anchors are kept at engageable positions even if their associated webbings, namely, the movable anchors are not at their occupant-restraining positions. When the movable anchors are brought to their respective occupant-restraining positions, the latches are tentatively moved to their non-engagement positions. When the movable anchors have then reached completely their corresponding occupant-restraining positions, the latches are again caused to return to their engagement positions and to engage their corresponding movable anchors.
On the other hand, it is generally necessary to provide with warning means which serves to determine whether the latch and its associated anchor are actually latched or not.
In a warning device of a conventional latch device having a latch which operates in the above-described manner, it is indispensable to provide two independent switch means for detecting the positions of both movable anchor and latch respectively in order to determine whether the latch and movable anchor are actually latched to each other since there is no direct relation between the latch's assuming the engagement position and the engagement of the latch with the movable anchor. Where the movable anchor is driven by electrical means such as motor or the like, it is necessary to provide switch means exclusively for warning the position of the latch, namely, for detecting the position of the latch in addition to switch means for detecting the arrival of the movable anchor at the occupant-restraining position and stopping the motor or the like.
Since the latch device requires two switch means as described above, there are such drawbacks that the reliability tends to become lower with respect to the actuation of the latch device, the dimensions of the latch device become greater, and its manufacturing cost increases.